The following meanings for the abbreviations used in this specification apply:
CN core network
CSG closed subscriber Group
HeNB home enhanced node B
HeNodeB home enhanced node B
HNodeB home node B
HNB home node B
MME mobility management entity
NW Network
PLMN public land mobile network
RNC radio network controller
RRC radio resource control
SAT SIM application toolkit
SI System Information
SIM subscriber identity module
SIB System Information Block
UE user equipment
UICC universal integrated circuit card
USAT USIM application toolkit
USIM universal subscriber identity module
In the E-UTRAN system there are conventional network access nodes/cells termed eNodeBs which serve all users, and also subscriber group Closed Subscriber Group (CSG) cells such as home eNodeBs which are available for traffic (voice and/or data) to only those subscribers registered with the CSG and possibly also certain allowed guests. Any given CSG may include a group of cells (such as a corporate or university campus) or a single cell. CSGs may allow traffic access for non-subscribers for emergency calls or routine, non-emergency access.
CSG cells are identified by a CSG identity (CSG ID) within a Public Land Mobile Network (PLMN). When a wireless transmit/receive unit or a user equipment (UE) accesses such a CSG cell, a network node, such as the Mobility Management Entity (MME), checks that the CSG ID of the CSG cell corresponds to a CSG ID in the CSG subscription data of the UE, and that the relevant validity criteria are met.
Furthermore, every time a UE enters or leaves the coverage area of a CSG cell or camps with it, it notifies a Universal Integrated Circuit Card (UICC) associated therewith in order to access a relevant application or applet on a Subscriber Identity Module (SIM), Universal Subscriber Identity Module (USIM), IP multimedia Services Identity Module (ISIM) or CDMA Subscriber Identity Module (CSIM) maintained on the UICC In particular, the notification is communicated by means of a SIM/USIM/ISIM/CSIM application toolkit envelope command of the type ‘event download—CSG cell selection’, and in response to receiving this notification, the UICC triggers any associated applications or applets for controlling access to the CSG cell, which may, for example, include accessing or releasing the resources of the CSG cell. Alternatively, the UICC may use this notification to monitor an operational state associated with the UE, which may, for example, be for checking compliance. The ‘event download—CSG cell selection’ inter alia communicates the CSG ID corresponding to the CSG cell and a selection status, Le, whether the user equipment is in the coverage of the CSG cell or whether it is camped on it.
As described above, a CSG ID uniquely identifies a CSG cell within a PLMN; in cases where the UE has access to a plurality of PLMNs, the identification of the CSG cell by the UICC can be arbitrary, and can affect operation of the applets and applications associated with the ‘event download—CSG cell selection’ command.
Some embodiments are directed towards providing an improved CSG cell selection notification mechanism.